Eosinophilic Meningoencephalitis

Abstract

The Angiostrongylus cantonensis is the most frequent infectious cause of eosinophilic meningoencephalitis in children in our settings. The definitive host of this nematode is the rat and the humans get infected by ingesting larvae in the third stage that are present in intermediate hosts like snails, carriers like shrimps and several fish that are eaten raw or bad cooked, or in fresh vegetables contaminated by the secretions of the snails. The ingested larvae enter in to the intestinal vases until they arrive to the meninges, where they die soon, producing an eosinophilic reaction, manifested as aseptic meningitis. From the at least 20 species of Angiostrongylus described, only two affect humans. The nematode Angiostrongylus cantonensis , the worm of the rat lung, is the most frequent cause of the eosinophilic meningitis. The Angiostrongylus (Parastrongylus) costaricensis is the causal agent of the abdominal or intestinal angiostrongyliasis. We describe the clinical symptoms of the eosinophilic meningitis, caused by the presence of larvae in the brain and by the local reactions of the host. In many cases, the patient can recover, but in some cases the evolution can be fatal, especially when the infection is massive.